Fluid analyzer with self-cleaning viewing windows

ABSTRACT

A turbidimeter or fluid analyzer having the light transmitting windows maintained clean by apparatus directing a flow of fluid thereupon.

United States Patent Shea [ FLUID ANALYZER WITH SELF-CLEANING VIEWINGWINDOWS [75] Inventor: James J. Shea, Dearborn Heights,

Mich.

[73] Assignee: Gam Rad, Inc., Detroit, Mich.

[22] Filed: Nov. 3, 1972 [21] Appl. No.: 303,631

[52] US. Cl 731/61 R, 137/238, 137/240, 250/239, 350/63, 356/208,356/246 [51] Int. Cl. G01n 21/26, G02b [58] Field of Search 137/240,238; 73/36, 61 R, 73/DIG.11, 355; 350/63 X; 251/118, 61;

[56] References Cited UNITED STATES PATENTS 1,924,139 8/1933 Thomas..250/218X 1 Jan. 21, 1975 2,185,361 1/1940 Townc 250/218 3,398,0238/1968 Jacobsen et al. 350/63 X 3,404,284 10/1968 Doolittle 350/63 UX3,453,049 7/1969 Wager, Jr. 350/63 X 3,628,028 12/1971 Thorsheim2.50/23) X Primary ExaminerAlan Cohan Assistant ExaminerR0bert J. MillerAttorney, Agent, or Firm-Zwcrdling, Maurcr, Diggs & Papp [57] ABSTRACT Aturbidimeter 0r fluid analyzer having the light transmitting windowsmaintained clean by apparatus directing a flow of fluid thereupon.

10 Claims, 5 Drawing Figures FLUID ANALYZER WITH SELF-CLEANING VIEWINGWINDOWS SUMMARY BACKGROUND OF THE INVENTION The present inventionrelates to turbidimeters and more particularly to a turbidimeter havingapparatus for cleaning the light transmitting windows.

With the recent emphasis on pollution control the potential applicationsfor turbidimeters or fluid analyzers as fluid flow monitors hasincreased. In some applications, however, the fluid to be monitored oranalyzed can be such as would deposit particles on or eventually coatthe windows; clearly the effectiveness of the device could be maintainedonly through periodic cleaning. In the present invention, this problemis solved by utilizing a flow of fluid over the window to clean and/orinsulate the window from contamination.

Therefore, it is an object of the present invention to provide a new andimproved turbidimeter having means for maintaining the lighttransmitting window clean.

In one form of the invention the window is maintained clean byproviding, in a sense, a curtain of water or other clean fluid,different from the monitored or analyzed fluid, across the window tomaintain a thin protective film or barrier thereacross. Thus it isanother object of the present invention to provide a turbidimeter of theabove described type having apparatus for providing a curtain or film offluid, different from the monitored fluid, across the light transmittingwindows to maintain them clean.

In another form of the invention, apparatus is provided to increase theflow of the monitored fluid on the area adjacent the windows and then tomaintain the windows clean by the velocity of the fluid or in adifferent form by turbulence. Thus it is another object of the presentinvention to provide a turbidimeter having apparatus for cleaning thelight transmitting windows by using the monitored fluid and by increasedvelocity across the windows and/or turbulence at the windows. It isstill another general object to provide for an improved turbidimeter.

Other objects, features, and advantages of the present invention willbecome apparent from the subsequent description and the appended claims,taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view taken generally along the lines11 of FIG. 2 of a turbidimeter having apparatus for providing a film offluid across the transmitting windows, which film of fluid is differentfrom the fluid being analyzed;

, FIG. 2 is a sectional view of a portion of the turbidimeter of FIG. 1and taken generally along the lines 22 of FIG. 1;

FIG. 3 is a fragmentary view of a modified flow tube for a turbidimetersimilar to that of FIG. 1 having a construction for providing a separateflow of fluid across the transmitting windows which is the same fluid asthat being analyzed;

. FIG. 4 is a fragmentary view of a different, modified flow tube inwhich all of the fluid to be monitored is directed through a restrictionadjacent the windows; and

FIG. 5 is a fragmentary sectional view of still another form of theinvention for providing a restriction adjacent the transmitting windows.

Looking now to FIG. 1, a turbidimeter or fluid analyzer is generallyshown and is indicated by the numeral 10 and includes a flow tubeassembly 12 and a support housing 14. The tube assembly 12 includes amain outer tube 16 which has a flange 18 at its outlet end and athreaded adaptor 20 secured to its inlet endflhe adaptor 20 receives theend of a pipe 22.

The main tube 16 has a necked down portion 24 intermediate its ends,which necked down portion is provided with a plurality of flatsincluding flats 26 and 28 which facilitate the mounting ofa light sourceassembly 30 and a sensor assembly 32. The light source assembly 30includes a lamp 33 which can be energized in a suitable source ofelectricity and the output of which can be sensed and regulated via aregulator 34; regulator 34 can be of a type well known in the art andhence the details thereof have been omitted for purposes of simplicity.The lamp 33 is connected to transmit its light through a lense assembly36 and thence into the necked down portion 24 of the flow tube I6 via awindow assembly 38. The window assembly 38 is connected to the flatportion 26 and includes a window 40 which has its inner surfacegenerally flush with the flat portion 26.

As can be seen from FIG. 2, the flat portion 28 is at quadrature withflat portion 26. Looking again to FIG. 1, the sensor assembly 32 isconnected to a lense assembly 42 which in turn is connected to a windowassembly 44. The window assembly 44 is connected to the flat portion 28and includes a window 46 which has its inner surface generally flushwith the flat portion 28. The sensor assembly 32 includes a suitablephotoresponsive member and can be connected to suitable outputindicating apparatus (not shown) whereby an indication of the turbidityof the fluid being analyzed can be obtained. The output indicatingapparatus can be of construction well'known in the art and hence adescription thereof has been omitted for purposes of simplicity.

As noted the turbidimeter 10, having the light source and photosensitivemember at a relative angle of operates on the Tyndall Effect. It shouldbe understood, however, that the present invention is not limited toTyndall Effect turbidimeters but can be used generally with anyturbidimeter or fluid analyzer having a window exposed to the fluidbeing analyzed. A window assembly 47 (FIG. 2) provides for pass throughof the light from source 30 and minimizes errors from reflected lightfrom that opposite wall.

An inner smaller diameter tube 48 has an enlarged end portion 50 whichis snugly, sealingly held to the inside diameter of adaptor 20. The tube48 extends generally up to the windows 40 and 46 and is in directcommunication with the pipe 22 such that the fluid to be analyzed willbe carried by the inner tube 48 and transmitted into the main tube 16 atthe windows 40 and 46 whereby the fluid will be exposed for analysis viathe light means 30 and sensor means 32.

The inner tube 48 has a reduced diameter portion 52 which defines anannular passageway 54 with the main tube 16; the inner tube 48terminates in a reduced diameter end portion 56 which is located inclose clearance relation to the necked down portion 24 and definestherewith a restricted passageway 58 which terminates just ahead of thewindows 40 and 46.

The end portion 56 is also provided with flats similar to the reduceddiameter portion 24.

An inlet pipe 60 is connected to the main tube 16 at a position tocommunicate the annular passageway 54 and a source 62 of fluid. Thesource 62 can be varied to vary the pressure of the fluid to regulatethe velocity of fluid across the windows 40 and 46. While the preferredfluid from source 62 could be clean water any fluid which would notadversely affect the analysis of the fluid from pipe 22 can be used.

In operation, the clean fluid from source 62 is directed to flow acrossthe windows 40 and 46; the pres sure of the clean fluid from the source62 is selected such that the velocity of clean fluid from the restrictedpassage 58 is sufficient to provide a thin film or curtain across thewindows 40 and 46 to, in a sense, insulate them from the fluid beinganalyzed. The pressure at the exit of passageway 58 is also selected tobe sufficiently high to assure that the fluid to be analyzed, from pipe22, will not back up into passageway 54. Thus with the design of FIG. 1,the windows 40 and 46 will be main tained clean from contamination bythe film or curtain of clean water or other suitable fluid from source62.

in the embodiments of FIG. 3-5 a separate fluid is not utilized and thewindows are maintained clean providing a curtain of film of the fluidbeing analyzed at an increase in velocity in the area adjacent thewindow so that the windows are maintained clean by a scrubbing actioncaused by the increased velocity and/or by turbulence. In thedescription of the embodiments of FIG. 3, 4 and 5, elements similar tolike elements in the embodiment of FIG. I and 2 have been given the samenumeral designation with the addition of the letter postscripts a, b andc, respectively.

Looking now to FIG. 3, the need for fluid source 62 has been eliminatedand pipe 60a is now connected as a shunt from between passageway 54a andpipe 22a. Thus, a portion of the fluid to be analyzed flowing in pipe22a is bypassed into passageway 54a while the remainder flows throughinner tube 48a. The remainder of the construction is generally the sameas that of FIG. 1. It is known that the velocity of a fluid in a pipe isgreater at the center than at the outer extremity. However, by use ofthe fluid flow through the restriction (similar to restricted passageway58 of FIG. 1) the velocity of the fluid is increased over what it wouldhave been if the outer tube 12a had been used alone in the conventionalmanner. Thus, the fluid in passage 54a is discharged adjacent thewindows and at an increase in velocity; hence, the windows aremaintained clean by the scrubbing action of the film of fluid flowingthereacross at an increase in velocity.

In the embodiment of FIG. 3 an auxiliary pump 67 is supplied in line 60ato raise the pressure in line 60a to a level to provide the desired flowthrough the restriction (similar to 58) for the cleaning purpose noted.Alternatively a flow restriction could be provided (in lieu of pump 67)in tube 50a to provide the necessary differential in pressure betweenthe fluid on tube 50a and that in tube 60a to provide the desired flowthrough the restriction (similar to 58).

Looking now to FIG. 4, again the fluid to be analyzed is used tomaintain the windows clean. Here the inner tube 48b is blocked atopposite ends by plugs 64 and 66 and all of the fluid to be analyzed istransmitted to the passageway 54b and pipe 60b. Now all of the fluid tobe analyzed is transmitted through the restricted passageway 58b andflows across the windows 40b and 46b at an increased velocity. Inaddition because the fluid from restricted passageway 58b includes allofthe fluid flowing through the main tube 12b and the restrictedpassageway 58b opens abruptly into an enlarged volume as defined by thenecked down portion 24b adjacent the windows 40b, 4612, there will beturbulence in this enlarged volume. The turbulence and increase invelocity across the windows 40b, 46b will assist in maintaining thewindows 40b, 46b clean.

In the embodiment of FIG. 5 the inner tube has been omitted and now allof the fluid to be analyzed flows directly through the inner tube 12:-from the inlet pipe 22c. However, a flow restrictor 68 is supportedgenerally in the necked down portion 24c adjacent the windows 40c, 46cand defines a restricted passageway 58:" In the embodiment shown in FIG.5 the flow restrictor 68 is generally conically shaped and is supportedin the main tube via a plurality of legs 70. The restrictor 68terminates at its large or base end in a plurality of flats 72 having anouter contour generally similar to the contour of the confrontingsurface of the flated, necked down portion 24c. The action of therestrictor 68 is similar to that of the closed inner tube 48b of FIG. 4in that it provides for both an increase in velocity of fluid acrosswindows 40c, 46c and also provides for turbulence in that area. Thisaction will assist in maintaining the windows 40c, 46c clean.

Note that the analysis or indication or turbidity is not affected by thevelocity of the fluid or by the turbulence of the fluid and hence theapparatus of the embodiment of FIGS. l5 will not affect the analysisbeing made.

Thus, in each of the embodiments shown, there is provided apparatus forself-cleaning of the windows whereby the frequency of maintenance can bereduced.

While it will be apparent that the preferred embodiments of theinvention disclosed are well calculated to fulfill the objects abovestated, it will be appreciated that the invention is susceptible tomodification, variation and change without departing from the properscope or fair meaning of the invention.

I claim:

1. A fluid analyzer comprising an annular, elongated flow tube, saidtube having at least one window whereby the fluid can be analyzed, andflow means operatively connected to said flow tube for directing fluidflow across the surface of said window in said tube whereby said surfaceof said window will be maintained clean, said flow tube including meansfor transmitting the fluid to be analyzed through a first passagewaypast said window whereby the analyzed fluid can be viewed and with saidflow means comprising separate passage means for directing fluid acrossthe surface of said window via a second passageway separate from saidfirst passageway, said flow means comprising a different annularelongated tube supported within said flow tube and defining with saidflow tube said first and second passageways.

2. A fluid analyzer comprising a flow tube, said tube having at leastone window whereby the fluid can be analyzed, and flow means operativelyconnected to said flow tube for directing fluid flow across the surfaceof said window in said tube whereby said surface of said window will bemaintained clean, said flow tube including means for transmitting thefluid to be analyzed through a first passageway past said window wherebythe analyzed fluid can be viewed and with said flow means comprisingseparate passage means for directing fluid across the surface of saidwindow via a second passageway separate from said first passageway, saidflow means comprising shunt means for receiving a portion of the fluidto be analyzed and directing that portion across the surface of saidwindow.

3. A fluid analyzer comprising a flow tube, said tube having at leastone window whereby the fluid can be analyzed, and flow means operativelyconnected to said flow tube for directing fluid flow across the surfaceof said window in said tube whereby said surface of said window will bemaintained clean, said flow means directing fluid to be analyzed acrossthe surface of said window.

4. The analyzer of claim 1 with said flow means transmitting all of thefluid to be analyzed.

5. A fluid analyzer comprising a flow tube, said tube having at leastone window whereby the fluid can be analyzed, and flow means operativelyconnected to said flow tube for directing fluid flow across the surfaceof said window in said tube whereby said surface of said window will bemaintained clean, said flow means comprising flow restrictor meanslocated approximate to said window for providing fluid flow at anincreased velocity.

6. The analyzer of claim 5 with said flow restrictor means defining arestricted passageway and with said tube adapted to transmit all of thefluid to be analyzed through said restricted passageway.

7. The analyzer of claim 6 with said restricted passageway terminatingadjacent said window and communicating therewith a substantiallyincreased volume whereby the fluid flow will be turbulent in thevicinity of the surface of said window.

8. The analyzer of claim 7 with said flow restrictor means comprising aclosed tube supported within said flow tube and located to define saidrestricted passageway.

9. The analyzer of claim 7 with said flow restrictor means comprising agenerally conically shaped member located to define said restrictedpassageway with the base downstream.

10. The fluid analyzer of claim 9 with said base having a contoursimilar to the contour of the confronting

1. A fluid analyzer comprising an annular, elongated flow tube, saidtube having at least one window whereby the fluid can be analyzed, andflow means operatively connected to said flow tube for directing fluidflow across the surface of said window in said tube whereby said surfaceof said window will be maintained clean, said flow tube including meansfor transmitting the fluid to be analyzed through a first passagewaypast said window whereby the analyzed fluid can be viewed and with saidflow means comprising separate passage means for directing fluid acrossthe surface of said window via a second passageway separate from saidfirst passageway, said flow means comprising a different annularelongated tube supported within said flow tube and defining with saidflow tube said first and second passageways.
 2. A fluid analyzercomprising a flow tube, said tube having at least one window whereby thefluid can be analyzed, and flow means operatively connected to said flowtube for directing fluid flow across the surface of said window in saidtube whereby said surface of said window will be maintained clean, saidflow tube including means for transmitting the fluid to be analyzedthrough a first passageway past said window whereby the analyzed fluidcan be viewed and with said flow means comprising separate passage meansfor directing fluid across the surface of said window via a secondpassageway separate from said first passageway, said flow meanscomprising shunt means for receiving a portion of the fluid to beanalyzed and directing that portion across the surface of said window.3. A fluid analyzer comprising a flow tube, said tube having at leastone window whereby the fluid can be analyzed, and flow means operativelyconnected to said flow tube for directing fluid flow across the surfaceof said window in said tube whereby said surface of said window will bemaintained clean, said flow means directing fluid to be analyzed acrossthe surface of said window.
 4. The analyzer of claim 1 with said flowmeans transmitting all of the fluid to be analyzed.
 5. A fluid analyzercomprising a flow tube, said tube having at least one window whereby thefluid can be analyzed, and flow means operatively connected to said flowtube for directing fluid flow across the surface of said window in saidtube whereby said surface of said window will be maintained clean, saidflow means comprising flow restrictor means located approximate to saidwindow for providing fluid flow at an increased veLocity.
 6. Theanalyzer of claim 5 with said flow restrictor means defining arestricted passageway and with said tube adapted to transmit all of thefluid to be analyzed through said restricted passageway.
 7. The analyzerof claim 6 with said restricted passageway terminating adjacent saidwindow and communicating therewith a substantially increased volumewhereby the fluid flow will be turbulent in the vicinity of the surfaceof said window.
 8. The analyzer of claim 7 with said flow restrictormeans comprising a closed tube supported within said flow tube andlocated to define said restricted passageway.
 9. The analyzer of claim 7with said flow restrictor means comprising a generally conically shapedmember located to define said restricted passageway with the basedownstream.
 10. The fluid analyzer of claim 9 with said base having acontour similar to the contour of the confronting surface of said flowtube.